Volatiles and their stable isotopes in volcanic materials are recurring themes of my research. Because of their special type of behavior in geological environments, volatiles can be used to extract unique information about the mantle and magmatic processes that is unaccessible for other classes of elements. Our research group targets specific isotope systems such as sulfur, boron, oxygen and hydrogen in Icelandic basalts in order to understand how and why the Icelandic mantle is heterogeneous. In the special case of Kverkfjöll, we look at all of these isotopes in a single volcanic system. I also study chlorine isotopes in rhyolites and fluid-rock reactions in ferrocarbonatites.
What are volatile elements?
In a cosmochemistry, elements are classified as refractory or volatile. Refractory elements (for example Al, Mg, Ti, Ca, Fe, Ni, REEs) have high condensation temperatures and are the first to precipitate out of the cooling (pre-)solar nebula as oxide or silicate minerals or metallic alloys. Volatile elements (for example H, He, C, Na, S, K, Hg, Pb) are those with low condensation temperatures, that is, elements that remain gaseous above temperatures of c. 1300 K at low pressures. However, this classification is neither intuitive or practical when considering the geochemical behaviour of elements in magmatic environments on Earth. For example, K and Na that are volatile in a cosmochemical sense, are usually rock-forming elements on Earth. For this reason, igneous geochemists classify volatile elements and compounds as those that partition strongly to fluid phases during magmatic processes and tend to be liquids or gases at room temperature and atmospheric pressure. Whenever I talk casually about volatiles, it is in this latter sense.